Mounting assemblies are commonly used in rotational power equipment to secure an abrasive wheel, grinding stone or circular blade (generally "cutting tool") to a motor drive shaft to allow for the rotational movement of the cutting device. Such mounting assemblies generally utilize a pair of mounting plates or flanges between which the cutting tool is held and supported. One of the mounting plates usually includes a spindle for receiving the cutting tool and the other mounting plate. The other plate includes a bore for receiving the spindle, and a retaining nut or fastener threaded on the spindle to hold the plates together and frictionally grip the cutting device. A drive connection, such as a woodruff key or spline, is employed to transfer power between the drive shaft of the power equipment and the spindle and the mounting plates.
During use, dynamic forces can cause a threaded fastener on the spindle to loosen in the mounting assembly. One method to overcome this problem is to manufacture the spindle with either left- or right-hand threads as dictated by the direction of drive rotation. However, requiring left- or right-hand threads requires extra parts inventory. Furthermore, users may make mistakes in identifying the thread direction in the spindle and therefore order the wrong parts.